# Post-Exercise Appetite and Ad Libitum Energy Intake in Response to High-Intensity Interval Training versus Moderate- or Vigorous-Intensity Continuous Training among Physically Inactive Middle-Aged Adults

PMID: 30279345
Journal: Nutrients
Published: 2018 Oct 2
Authors: Poon ET, Sun FH, Chung AP, Wong SH

## Question

Does a single practical HIIT treadmill session change post-exercise appetite or ad libitum energy intake differently than moderate- or vigorous-intensity continuous training in inactive middle-aged men?

## Summary

This randomized crossover lab study tested one HIIT, one moderate continuous, and one vigorous continuous treadmill session in 11 physically inactive middle-aged men. HIIT used 10 x 1-minute runs at 100% VO2max with 1-minute active recovery. Post-exercise buffet intake and subjective appetite did not differ between exercise types, even though MICT used more exercise energy and HIIT/VICT produced higher lactate. All participants completed the study without adverse events.

## Population

- Eleven healthy physically inactive middle-aged men aged 40-59 years.
- Sample size: 11
- Age: 45.7 +/- 7.4 years
- Sex: Male
- Fitness level: Physically inactive; no structured exercise or dieting program in past year.
- Health status: Healthy and screened to exclude high cardiovascular risk and major recent cardiac events.

## Methodology

- Randomized crossover acute exercise trial with three treadmill conditions.
- Three experimental trials at 1-week intervals after preliminary testing and familiarization.
- Exercise laboratory treadmill testing with standardized breakfast and buffet meal.
- Randomized and controlled study design.

## Protocol

- HIIT treadmill.
- Modality: Treadmill running.
- Work intervals: 10 x 1 minute at 100% VO2max.
- Recovery: 1 minute active recovery at 50% VO2max.
- Sets or repetitions: 10 intervals.
- Intensity: 100% VO2max work bouts.
- Session duration: 20-minute interval protocol plus 2-minute warm-up and 2-minute cool-down.
- Frequency: Single acute trial.
- Program length: One session.
- Progression: None.
- MICT and VICT.
- Modality: Treadmill running.
- Work intervals: Continuous running.
- Sets or repetitions: One continuous bout.
- Intensity: MICT 65% VO2max for 40 minutes; VICT 80% VO2max for 20 minutes.
- Session duration: MICT 40 minutes; VICT 20 minutes, each plus 2-minute warm-up and cool-down.
- Frequency: Single acute trial per condition.
- Program length: One session each.
- Progression: None.

## Outcomes

### Ad libitum energy intake
Status: no clear change
Post-exercise buffet energy intake did not differ between HIIT, MICT, and VICT.

HIIT 645 +/- 262.9 kcal; MICT 614.7 +/- 271.2; VICT 623.1 +/- 249.0; p > 0.05.

### Subjective appetite
Status: no clear change
Appetite changed over time but did not differ by exercise protocol.

Main effect of time p < 0.01; no protocol or interaction effects, p > 0.05.

### Energy expenditure and lactate
Status: mixed
MICT used more exercise energy; HIIT and VICT were energy matched and produced higher lactate than MICT.

EE MICT 365 +/- 43 kcal > HIIT 216 +/- 29 and VICT 222 +/- 32, p < 0.01; lactate HIIT and VICT 5.1 mmol/L > MICT 1.7 mmol/L, p < 0.05.

### Safety/completion
Status: improved
All participants completed the study and no adverse events were reported.

11/11 completed all trials.

## Practical Insights

- This practical HIIT session did not acutely suppress appetite compared with continuous exercise.
- HIIT also did not increase immediate buffet intake.
- Weight-management claims should not rely on appetite suppression from standard HIIT alone.

## Limitations

- Small sample.
- Male-only and healthy inactive sample.
- No appetite hormone measurement.
- Only acute post-exercise period measured.
- Large individual variability in energy intake.

## Safety And Adherence

- No adverse events were reported.
- Participants were screened for high cardiovascular risk.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/30279345/) (pubmed)
- [DOI](https://doi.org/10.3390/nu10101408) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6213307/) (full text)

## Agent Guidance

Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.